A coherent microwave photonic link for shortwave or ultrashortwave broadband transmission

Abstract

The embodiment of the present invention provides a coherent microwave photonic link for short-wave or ultra-short-wave broadband transmission. Due to the existence of the phase-locked loop, the phases of the first narrow-linewidth laser and the second narrow-linewidth laser change synchronously, and the phases of the second narrow-linewidth laser are always kept the same. The frequency is in phase, avoiding the power jitter of the radio frequency signal caused by the phase jitter in the long-distance optical fiber; and the linewidth of the two narrow linewidth lasers is narrow, which can control the frequency difference between the optical signals output by the two narrow linewidth lasers Within the frequency-locked range of the phase-locked loop, phase loss of lock when transmitting short-wave or ultra-short-wave signals is avoided. The problem of severe power attenuation in coherent microwave photonic links for short-wave or ultra-short-wave broadband transmission and radio frequency signal power jitter caused by fiber jitter is solved. Based on the digital demodulation technology at the receiving end, while reducing the digital noise of the broadband demodulated signal, it can effectively suppress the nonlinear distortion of the broadband cross-octave signal, thereby realizing a coherent microwave photonic link with a wide bandwidth and a large dynamic range.

Description

technical field [0001] The invention relates to the field of communication technology, in particular to a coherent microwave photonic link oriented to short-wave or ultra-short-wave broadband transmission. Background technique [0002] Microwave photonics is a subject that uses optical methods to realize microwave signal processing. As the core of optical processing, microwave photonic link can realize processing functions such as conversion between microwave and light wave and transmission. Microwave photonic links have extremely wide application value in many fields such as radar positioning, wireless communication, electronic countermeasures, satellite communication, and television broadcasting. [0003] In the microwave photonic link, the radio frequency signal is modulated to the optical carrier, and then demodulated after being propagated through the optical fiber to restore the original radio frequency signal. The coherent microwave photonic link for short-wave or u...

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Problems solved by technology

[0006] The purpose of the embodiments of the present invention is to provide a coherent microwave photonic link for short-wave or ultra-short-wave broadband transmission, which is used to solve the problem that the power of the received signal in the microwave photonic link structure with a large dynamic range in the prior art is greatly affected by fiber jitter , the power attenuation is also relatively serious, so it is difficult to realize short-wave or ultra-short-wave long-distance transmission

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